/*
 * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
 *
 * Copyright (C) 2002-2011 Aleph One Ltd.
 *   for Toby Churchill Ltd and Brightstar Engineering
 *
 * Created by Charles Manning <charles@aleph1.co.uk>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

/*
 * This is an interface module for handling NOR in yaffs1 mode.
 */

/* This code is intended to be used with "regular" NOR that is bit-modifyable.
 *
 * Each "chunk" is a contguous area of 512 + 16 bytes.
 * This makes 248 such chunks with some space left over where a format markerr
 * is stored.
 */

#include "yaffs_nor_drv.h"

#include "yportenv.h"
#include "yaffs_trace.h"

#include "yaffs_flashif.h"
#include "yaffs_guts.h"

/* Tunable data */
#define DATA_BYTES_PER_CHUNK  512
#define SPARE_BYTES_PER_CHUNK 16
#define BLOCK_SIZE_IN_BYTES   (128 * 1024)
#define BYTES_IN_DEVICE       (4 * 1024 * 1024)

#define BYTES_PER_CHUNK       (DATA_BYTES_PER_CHUNK + SPARE_BYTES_PER_CHUNK)
#define SPARE_AREA_OFFSET     DATA_BYTES_PER_CHUNK
#define CHUNKS_PER_BLOCK      (BLOCK_SIZE_IN_BYTES / BYTES_PER_CHUNK)

#define BLOCKS_IN_DEVICE      (BYTES_IN_DEVICE / BLOCK_SIZE_IN_BYTES)

#define YNOR_PREMARKER        (0xF6)
#define YNOR_POSTMARKER       (0xF0)

#define FORMAT_OFFSET         (CHUNKS_PER_BLOCK * BYTES_PER_CHUNK)
#define FORMAT_VALUE          0x1234

#if 1

/* Compile this for a simulation */
#include "ynorsim.h"

static struct nor_sim *nor_sim;

#define nor_drv_FlashInit() \
    do { nor_sim = ynorsim_initialise("emfile-nor", BLOCKS_IN_DEVICE, BLOCK_SIZE_IN_BYTES); } \
    while (0)
#define nor_drv_FlashDeinit()                   ynorsim_shutdown(nor_sim)
#define nor_drv_FlashWrite32(addr, buf, nwords) ynorsim_wr32(nor_sim, addr, buf, nwords)
#define nor_drv_FlashRead32(addr, buf, nwords)  ynorsim_rd32(nor_sim, addr, buf, nwords)
#define nor_drv_FlashEraseBlock(addr)           ynorsim_erase(nor_sim, addr)
#define DEVICE_BASE ynorsim_get_base(nor_sim)

#else

/* Compile this to hook up to read hardware */
#include "../blob/yflashrw.h"
#define nor_drv_FlashInit() \
    do {} \
    while (0)
#define nor_drv_FlashDeinit() \
    do {} \
    while (0)
#define nor_drv_FlashWrite32(addr, buf, nwords) Y_FlashWrite(addr, buf, nwords)
#define nor_drv_FlashRead32(addr, buf, nwords)  Y_FlashRead(addr, buf, nwords)
#define nor_drv_FlashEraseBlock(addr)           Y_FlashErase(addr, BLOCK_SIZE_IN_BYTES)
#define DEVICE_BASE (32 * 1024 * 1024)
#endif /* if 1 */


static u32 *Block2Addr(struct yaffs_dev *dev, int blockNumber)
{
    u8 *addr;

    dev   = dev;

    addr  = (u8 *)DEVICE_BASE;
    addr += blockNumber * BLOCK_SIZE_IN_BYTES;

    return (u32 *)addr;
}

static u32 *Block2FormatAddr(struct yaffs_dev *dev, int blockNumber)
{
    u8 *addr;

    addr  = (u8 *)Block2Addr(dev, blockNumber);
    addr += FORMAT_OFFSET;

    return (u32 *)addr;
}

static u32 *Chunk2DataAddr(struct yaffs_dev *dev, int chunk_id)
{
    unsigned block;
    unsigned chunkInBlock;
    u8 *addr;

    block = chunk_id / dev->param.chunks_per_block;
    chunkInBlock = chunk_id % dev->param.chunks_per_block;

    addr  = (u8 *)Block2Addr(dev, block);
    addr += chunkInBlock * BYTES_PER_CHUNK;

    return (u32 *)addr;
}

static u32 *Chunk2SpareAddr(struct yaffs_dev *dev, int chunk_id)
{
    u8 *addr;

    addr  = (u8 *)Chunk2DataAddr(dev, chunk_id);
    addr += SPARE_AREA_OFFSET;
    return (u32 *)addr;
}


static void nor_drv_AndBytes(u8 *target, const u8 *src, int nbytes)
{
    while (nbytes > 0) {
        *target &= *src;
        target++;
        src++;
        nbytes--;
    }
}

static int nor_drv_WriteChunkToNAND(struct yaffs_dev *dev, int nand_chunk,
                                    const u8 *data, int data_len,
                                    const u8 *oob, int oob_len)
{
    u32 *dataAddr  = Chunk2DataAddr(dev, nand_chunk);
    u32 *spareAddr = Chunk2SpareAddr(dev, nand_chunk);

    struct yaffs_spare *spare = (struct yaffs_spare *)oob;
    struct yaffs_spare tmpSpare;

    (void)oob_len;

    /* We should only be getting called for one of 3 reasons:
     * Writing a chunk: data and spare will not be NULL
     * Writing a deletion marker: data will be NULL, spare not NULL
     * Writing a bad block marker: data will be NULL, spare not NULL
     */

    if (sizeof(struct yaffs_spare) != SPARE_BYTES_PER_CHUNK) {
        BUG();
    }

    if (data && oob) {
        if (spare->page_status != 0xff) {
            BUG();
        }
        /* Write a pre-marker */
        memset(&tmpSpare, 0xff, sizeof(tmpSpare));
        tmpSpare.page_status = YNOR_PREMARKER;
        nor_drv_FlashWrite32(spareAddr, (u32 *)&tmpSpare, sizeof(struct yaffs_spare) / sizeof(u32));

        /* Write the data */
        nor_drv_FlashWrite32(dataAddr, (u32 *)data, data_len / sizeof(u32));

        memcpy(&tmpSpare, spare, sizeof(struct yaffs_spare));

        /* Write the real tags, but override the premarker*/
        tmpSpare.page_status = YNOR_PREMARKER;
        nor_drv_FlashWrite32(spareAddr, (u32 *)&tmpSpare, sizeof(struct yaffs_spare) / sizeof(u32));

        /* Write a post-marker */
        tmpSpare.page_status = YNOR_POSTMARKER;
        nor_drv_FlashWrite32(spareAddr, (u32 *)&tmpSpare, sizeof(tmpSpare) / sizeof(u32));
    } else if (spare) {
        /* This has to be a read-modify-write operation to handle NOR-ness */

        nor_drv_FlashRead32(spareAddr, (u32 *)&tmpSpare, sizeof(struct yaffs_spare) / sizeof(u32));

        nor_drv_AndBytes((u8 *)&tmpSpare, (u8 *)spare, sizeof(struct yaffs_spare));

        nor_drv_FlashWrite32(spareAddr, (u32 *)&tmpSpare, sizeof(struct yaffs_spare) / sizeof(u32));
    } else {
        BUG();
    }

    return YAFFS_OK;
}

static int nor_drv_ReadChunkFromNAND(struct yaffs_dev *dev, int nand_chunk,
                                     u8 *data, int data_len,
                                     u8 *oob, int oob_len,
                                     enum yaffs_ecc_result *ecc_result)
{
    struct yaffs_spare *spare = (struct yaffs_spare *)oob;

    u32 *dataAddr  = Chunk2DataAddr(dev, nand_chunk);
    u32 *spareAddr = Chunk2SpareAddr(dev, nand_chunk);

    if (data) {
        nor_drv_FlashRead32(dataAddr, (u32 *)data, dev->param.total_bytes_per_chunk / sizeof(u32));
    }

    if (oob) {
        nor_drv_FlashRead32(spareAddr, (u32 *)spare, oob_len / sizeof(u32));

        /* If the page status is YNOR_POSTMARKER then it was written properly
         * so change that to 0xFF so that the rest of yaffs is happy.
         */
        if (spare->page_status == YNOR_POSTMARKER) {
            spare->page_status = 0xff;
        } else if (spare->page_status != 0xff &&
                   (spare->page_status | YNOR_PREMARKER) != 0xff) {
            spare->page_status = YNOR_PREMARKER;
        }
    }

    if (ecc_result) {
        *ecc_result = YAFFS_ECC_RESULT_NO_ERROR;
    }

    return YAFFS_OK;
}


static int nor_drv_FormatBlock(struct yaffs_dev *dev, int blockNumber)
{
    u32 *blockAddr  = Block2Addr(dev, blockNumber);
    u32 *formatAddr = Block2FormatAddr(dev, blockNumber);
    u32 formatValue = FORMAT_VALUE;

    nor_drv_FlashEraseBlock(blockAddr);
    nor_drv_FlashWrite32(formatAddr, &formatValue, 1);

    return YAFFS_OK;
}

static int nor_drv_UnformatBlock(struct yaffs_dev *dev, int blockNumber)
{
    u32 *formatAddr = Block2FormatAddr(dev, blockNumber);
    u32 formatValue = 0;

    nor_drv_FlashWrite32(formatAddr, &formatValue, 1);

    return YAFFS_OK;
}

static int nor_drv_IsBlockFormatted(struct yaffs_dev *dev, int blockNumber)
{
    u32 *formatAddr = Block2FormatAddr(dev, blockNumber);
    u32 formatValue;


    nor_drv_FlashRead32(formatAddr, &formatValue, 1);

    return formatValue == FORMAT_VALUE;
}

static int nor_drv_EraseBlockInNAND(struct yaffs_dev *dev, int blockNumber)
{
    if (blockNumber < 0 || blockNumber >= BLOCKS_IN_DEVICE) {
        yaffs_trace(YAFFS_TRACE_ALWAYS,
                    "Attempt to erase non-existant block %d\n",
                    blockNumber);
        return YAFFS_FAIL;
    } else {
        nor_drv_UnformatBlock(dev, blockNumber);
        nor_drv_FormatBlock(dev, blockNumber);
        return YAFFS_OK;
    }
}

static int nor_drv_InitialiseNAND(struct yaffs_dev *dev)
{
    int i;

    nor_drv_FlashInit();
    /* Go through the blocks formatting them if they are not formatted */
    for (i = dev->param.start_block; i <= dev->param.end_block; i++) {
        if (!nor_drv_IsBlockFormatted(dev, i)) {
            nor_drv_FormatBlock(dev, i);
        }
    }
    return YAFFS_OK;
}

static int nor_drv_Deinitialise_flash_fn(struct yaffs_dev *dev)
{
    dev = dev;

    nor_drv_FlashDeinit();

    return YAFFS_OK;
}


struct yaffs_dev *yaffs_nor_install_drv(const char *name)
{
    struct yaffs_dev *dev = malloc(sizeof(struct yaffs_dev));
    char *name_copy = strdup(name);
    struct yaffs_param *param;
    struct yaffs_driver *drv;


    if (!dev || !name_copy) {
        free(name_copy);
        free(dev);
        return NULL;
    }

    param = &dev->param;
    drv   = &dev->drv;

    memset(dev, 0, sizeof(*dev));

    param->name = name_copy;

    param->total_bytes_per_chunk = DATA_BYTES_PER_CHUNK;
    param->chunks_per_block = CHUNKS_PER_BLOCK;
    param->n_reserved_blocks     = 2;
    param->start_block       = 0; // Can use block 0
    param->end_block         = BLOCKS_IN_DEVICE - 1; // Last block
    param->use_nand_ecc      = 0; // use YAFFS's ECC
    param->disable_soft_del  = 1;

    drv->drv_write_chunk_fn  = nor_drv_WriteChunkToNAND;
    drv->drv_read_chunk_fn   = nor_drv_ReadChunkFromNAND;
    drv->drv_erase_fn        = nor_drv_EraseBlockInNAND;
    drv->drv_initialise_fn   = nor_drv_InitialiseNAND;
    drv->drv_deinitialise_fn = nor_drv_Deinitialise_flash_fn;

    param->n_caches = 10;
    param->disable_soft_del  = 1;

    dev->driver_context      = (void *)nor_sim;

    yaffs_add_device(dev);

    return NULL;
}
